Ground clamp



GROUND CLAMP Filed Jan. 22, 1960 INVENTORS H'rrehu/s Paul 0. C. JacksonF DJ United States Patent 3,046,511 GROUND CLAMP Cecil C. Rinehuls,Largo, Fla. (RD. 1, Box 76, Lake Millsite, Bartow, Fla.), and Paul 0. C.Jackson, 10720 59th Way N., Largo 2, Fla.

Filed Jan. 22, 1960, Ser. No. 4,112 1 Claim. (Cl. 339-13) This inventionrelates to ground clamps and more particularly to a ground clamp capableof being used with various sizes of conduit or electrical metal tubing,cable or. other commonly used electrical conductors.

An object of the invention is to provide a mechanically simple andpractical ground clamp which will serve its intended purpose veryeffectively, Often, ground connections are concealed in buildings, eventhough this is poor practice. Then, if a faulty ground condition occurs,there is considerable ditliculty in first finding the location of theground connection and second, obtaining access to it. Furthermore,sources of electrical difliculties indicate checking the ground clamp,even though the ground connection is not faulty. When the ground connection is not readily accessible, the same difficulties areencountered.

In those cases where the ground connection is actually faulty, thereappears to be little or no excuse for this because faulty grounds oftenoccur after long periods of satisfaction.

An object of this invention is to provide an easily applied ground clampwhich will assure an excellent ground for an electrical system not onlyat original installation but for an indefinite period.

An important feature of the invention is found in the adaptability ofthe clamp to receive more than one commonly used size of conduit,E.M.T., BX, etc.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more full hereinafter described and claimed, referencebeing had to the accompaanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout, and in which: 7

FIGURE 1 is a perspective view showing the ground clamp in use;

FIGURE 2 is a sectional view taken on the line 2-2 of FIGURE 1; and IFIGURE 3 is an elevational view of the ground clamp shown inFIGURE 1.

In the accompanying drawings there isan illustration of a pipe 12 whichis assumed to be grounded and to which the wire 14 must be connected forelectrical continuity. The wire 14- could very easily be substituted bystranded wire, this being immaterial insofar as the principles of theinvention are concerned.

Ground clamp 16 is made of a first clamp section 18 and a second clampsection 20 and the sections are mechanically coupled together, forinstance, by screw 22 which serves a dual purpose. The first function ofthe screw 22 is to connect the sections 18 and 20, and the secondfunction, when applicable, is to function as a setscrew by having theextremity thereof engage pipe 12 as shown in FIGURE 2.

Clamp section 18 has two parts 24 and 26, each of which has a pair ofears 27, 28 and 29, 30 protruding 3,046,511 Patented July 24, 1962laterally outwardly from recessed intermediate parts 32 and 34,respectively. Screws 38 and 40 are passed through openings in ears 27,28 and are screwed into tapped openings in ears 29, 30 so that upontightening screws 38 and 40, the two parts 24 and 26 of clamp section 18are brought tightly to bear against the outer surface of pipe 12. Screw22 is engaged on a tapped opening in the intermediate part 34 of section18, and it is passed through an opening in plate 46 which extendslaterally outwardly from the. body 48 of section 20 and whichconstitutes a part of section 20.

Body 48 has a larger diameter cylindrical wall 50 and a smaller diametercylindrical wall 52, and the walls are integrally joined. Shoulder 54,which is circular, is at the juncture of walls 50* and 52 and forms anabutment or stop against which conduit 56, electrical metallic tubing,BX, etc. abuts. The cylindrical wall 52 is adapted to receive a smallerdiameter conduit '56 or the like. Consequently, there is a shoulder 60,formed by a circular flange, within cylindrical wall 52. The shoulder 60is located between the two ends of the wall 52.

There is means for engaging the conduit 56 or the like, regardless ofwhether it is positioned within the wall 52 or cylindrical wall 50. Thepreferred means consists of a pair of setscrews 64 and 66 located inthreaded openings in the walls 50 and 52. The set-screws are adapted tofirmly engage the outer surface of the side wall of the conduit 5 6.

Wire 14 is carried by conduit 56, and it extends beyond the end thereofso that a portion of the wire is located between pressure foot 68 andthe lower surface of wall 52. The pressure foot is swivelly connected toscrew 70, and the screw is passed through a tapped opening incylindrical wall 52. Screws 70, 66 and 64 have screwdriver slots thereinto facilitate turning of the screws, in other words, the screws areconventional.

In the use of ground connector 20, it is immediately evident that theground connector is 'athreadless ground connector in a sense that thethreading of the rigid conduit 56 is eliminated. When E.M.T. is in thebuilding or at least, used for housing the ground wire, an EMT.connector is eliminated. The ground wire is not exposed as it is securedinside the grounding clamp, and this pre vents damage to the groundwire. The installation of ground clamp 20 is certainly considerablyeasier for the electrician since all that he has to do is insert thewire into the clamp and tighten the grounding screw and EMT. screw.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not not desired tolimit the invention to the exact construction and operation shown anddescribed, and accordingly, all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention asclaimed.

What is claimed as new is as follows:

A grounding coupling for an electric conductor of the type including awire enclosed in a conduit, said coupling comprising a conductive sleevemounted on an end portion of the conduit in communication therewith andprojecting longitudinally therefrom, means for securing the sleeve onthe conduit, means for clamping the wire in the projecting end portionof the sleeve in contact therewith, and means for electricallyconnecting the sleeve to a grounding pipe, the last named meanscomprising a conductive clamp including a pair of opposed jaws forreceiving and gripping the pipe therebctween, "and a screw rotatablymounted on the sleeve and threaded through one of the jaws andengageable with the pipe for mounting the clamp on the sleeve and forfrictionally securing said clamp against slippage on the pipe, thesecond named means including a screw threadedly mounted in the sleeve,and a pressure foot swivelly mounted on the second named screw andengageahle with the wire for clamping same against the sleeve.

References fitted in the file of this patent UNITED STATES PATENTS OTHERREFERENCES Publication I Folder No. 39, Grouse-Hinds Co.

